Magnetostriction monitor for continuous vapor deposition processor



A. B. ENGELMANN DEPOSITION PROCESSOR 4 Sheets-Sheet 1 Filed Oct. 26, 1967 rlB POWER SOURCE TWISTER DRIVE POWER SOURCE SOURCE POWER DRIVE FIELD TAKE-UP REEL DRIVE FIELD POWER SOURCE E P I mm m P 00 P S M R E C M O U P O S m P LL Mm wmm H M II II R C LE AZ u 6 R R E E K-l ANN M W U l EMO 8 H S 5 D D E E Ewan m nw D P 8 l,

lNVENTOR ALFRED B. E/VGELMA/VIV WM ATTORNEY MAGNE'I'OSTRICTION MONITOR FOR CONTINUOUS VAPOR DEPOSITION PROCESSOR Filed Oct. 26, 1967 4 Sheets-Sheet 3 March 10, R970 A. B. ENGELMANN 3,499,790

MAGNETOSTRICTION MONITOR FOR CONTINUOUS VAPOR DEPOSITION PROCESSOR Filed Oct. 26, 196'? 4 Sheets-Sheet 5 March W, 1% A. B. ENGELMANN 3,

MAGNETOSTRICTION MONITOR FOR CONTINUOUS VAPOR DEPOSITION PROCESSOR 4 Sheets-Sheet 4 Filed Oct. 26, 1967 m-zm CW SAMPLE PERIOD STRESS ROTATION TIMING CAM United States Patent O 3,499,790 MAGNETOSTRHCTION MONITOR FOR CONTINU- OUS VAPOR DEPOSITION PROCESSOR Alfred B. Engelmann, Burnsville, Minn., assignor to Sperry Rand Corporation, New York, N.Y., a corporation of Delaware Filed Oct. 26, 1967, Ser. No. 678,448 Int. Cl. C23c 13/04; B44d 1/50; G03g 19/00 US. Cl. 117238 9 Claims ABSTRACT OF THE DISCLOSURE A device for and a method of monitoring the varying magnetostrictive characteristics of a deposited-layer element, or test-film, during the generation thereof by applying cyclical stresses thereto and detecting the resulting varying switching field thereof. Provision is made for the monitoring of a separate test-film for each deposition step in a continuous series of discrete deposition steps.

The invention herein described was made in the course of or under a contract or subcontract thereunder with the Department of the Army.

BACKGROUND OF THE INVENTION The present invention relates to the metal treating art and in particular to the generation of deposited-layer elements having the property of magnetostriction. A material that when subjected to a magnetic field undergoes a change in its dimensional characteristics or that when subjected to a stress undergoes a change in its magnetic characteristics is said to be magnetoelastic. These magnetoelastic cfiects are known as magnetostriction. There are two general classes of magnetostrictive materials-those that have positive and those that have negative magnetostriction when subjected to a unidirectional stress. With an element composed of a material having positive magnetostriction the elements magnetization M is increased by an applied tensile stress (or decreased by an applied compressive stress) and its dimensions increase with an applied magnetic field. Correlatively, with an element composed of a material having negative magnetostriction the elements magnetization M is decreased by an applied tensile stress (or increased by an applied compressive stress) and its dimensions decrease with an applied magnetic field. The fractional change in the elements dimension, as for example its length, due to magnetostriction varies with the intensity of the applied magnetic field or stress.

The P. E. Oberg et al., Patent No. 3,336,154 discloses a specially developed test apparatus that is placed in the environment in which the deposited-layer elements are to be generated; the applicable environment being that disclosed in the S. M. Rubens et al., Patent No. 2,900,282 and Patent No. 3,155,561 which environment includes an evacuatable enclosure in which deposited-layer elements of a magnetostrictive material are formed by the vapor deposition of a magnetostrictive material upon a suitable substrate member. The vaporized material is deposited on a test substrate member held in the test apparatus in the same manner as it is deposited on the production substrates. A test-film, of the same material as the production run elements, having a substantial width and length is deposited on the test substrate member which is clamped between two opposing, convex-surfaced, support ing members. The test substrate member is held on its opposite ends by a pair of clamps that aredriven by a cam, cam-follower and rocker-arm arrangement, which arrangement cyclically flexes the test substrate member as it alternately pulls up on and pushes down on the test substrate member ends. This flexing of the test substrate member induces alternate tensile and compressive stresses into the test-film while it is being deposited on the bottom surface of the test substrate member.

Besides a DC orienting field of approximately 45 oersteds (0e), which may be utilized for the orienting of the material to produce the required unaxial anisotropy in the production run elements, an AC field of approximately 55 oersteds is applied to the test-film so as to apply a drive field to the test-film. The direction of the test-films magnetization M is effected by the drive field thereby generating a switching field that is detected by a pickup coil mounted in a superposed relationship above the test-film. There is generated in the pickup coil a test signal that is indicative of the switching fields characteristics. The test signal may be suitably amplified and displayed upon a monitor oscilloscope and visually observed and analyzed by an operator who may control the generation of the production run elements so as to achieve a finished product having the desired magnetostriction characteristics. Alternatively, the test signal may be coupled to a signal analyzer that through the proper feedback arrangement would control the generation of the test-film and, correspondingly, the production run elements.

This above P. E. Oberg et al., patent requires that after the generation of the production run elements and, correspondingly, the test-film, the evacuatable enclosure in which the deposited layer elements are generated must be broken down, i.e., all electrical power and vacuum removed, whereby the production run elements and the test-film may be removed and new production substrates and a new test substrate inserted into the system. However, in a continuous vacuum deposition system such as disclosed in the copending patent application of C. J. Bukkila et al., Ser. No. 547,619, filed May 4, 1966, assigned to the Sperry Rand Corporation as is the present invention, it is not possible to break down the system whereby new test substrates may be inserted therein for each deposition step. Accordingly, it is desirable that there be provided a device for and a method of monitoring a separate deposited layer element, or test-film, for each deposition step in a continuous series of discrete deposition steps without requiring deposition system break down between discrete deposition steps. Accordingly, it is a primary object of the present invention to provide an improved magnetostriction monitor for a continuous vapor deposition processor.

SUMMARY OF THE INVENTION The present invention may be considered an improvement type invention over that of the P. E. Oberg et al. patent in that the present invention provides for the monitoring of a separate deposited layer element, or testfilm, for each deposition step in a continuous series of discrete deposition steps without requiring deposition system breakdown between discrete deposition steps. The present invention, in the preferred embodiment, utilizes a novel test apparatus that is placed in the environment in which the deposited-layer elements are to be generated. The vaporized material is deposited on a small portion of a continuous glass ribbon, which functions as a test substrate, in the same manner as it is deposited on the production substrates. The continuous glass ribbon is fed from a supply reel through a twister mechanism over a suitable mask for defining the area on the glass ribbon upon which the vaporized material is to be deposited, then through a guide means and finally upon a tape-up reel. Above the glass ribbon in the area in which the vaporized material is to be deposited is oriented a pickup coil for detecting changes in the switching field of the sodeposited vaporized material. The twister mechanism, through a cam and linkage arrangement, is caused to rotate in alternate directions of rotation inducing a torsional stress in the glass ribbon and, correspondingly, the

vaporized material deposited thereon. Suitable timing controls are provided to properly time, or gate, the pickup coil signals and the associated electronics with the twisting action of the twister mechanism and the correspondingly produced varying switching field in the test-film under the pickup coil.

After the completion of the monitoring of the separate test-film for each deposition step in the continuous series of discrete deposition steps and in between such adjacent deposition steps the continuous glass ribbon take-up reel is energized causing a new portion of the glass ribbon to be placed above the test-film mask whereby a new test-film, during the next subsequent deposition step, may be deposited. Accordingly, the present invention provides for the monitoring of a separate test-film for each deposition step in a continuous series of discrete deposition steps without requiring deposition system breakdown between discrete deposition steps.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a set-up that may be utilized to practice the present invention.

FIG. 2 is a schematic illustration of the evacuatable environment in which the deposited layer elements of the present invention may be generated.

FIG. 3 is a near side view of the test apparatus of the present invention.

FIG. 4 is a top view of the test apparatus of the present invention.

FIG. 5 is a cross-sectional view of the test apparatus of the present invention taken along axis 55 of FIG. 3.

FIG. 6 is a partial top view of the test apparatus of the present invention taken along axis 66 of FIG. 3.

FIG. 7 is an end view of the guide means of the test apparatus of the present invention taken along axis 7-7 of FIG. 6.

FIG. 8 is an end view of the guide means of the test apparatus of the present invention taken along axis 88 of FIG. 6.

FIG. 9 is a partial end view of the twister cam, cam follower and timing cam arrangement of the test apparatus of the present invention taken along axis 99 of FIG. 3.

FIG. 10 is a partial side view of the timing cam and timing switch arrangement of the test apparatus of the present invention taken along axis 10-10 of FIG. 9.

FIG. 11 is a schematic illustration of the orientation of the DC orienting field, the pulsed DC field coil, the drive field coil, the pick-up coil and the cyclical torsional stresses with respect to the deposited layer element on the ribbon substrate of the present invention.

FIG. 12 is a plot of the angular rotation of the timing cam versus the stress induced in the deposited layer element of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT System description With particular reference to FIG. 1, there is illustrated a block diagram of a set-up that may be utilized to practice the present invention. The evacuatable environment for the generation of test-film 10 on glass ribbon 12 is achieved by evacuatable enclosure 14 which forms a sealed enclosure whose internal pressure is controlled by pump 16 and pump power source 18. Stress is induced in test-film 10 by way of motor 20 and power source 22 which impart, through appropriate mechanical means, cyclical tensile or compressive stresses to substrate 12 and, accordingly, test-film 10. A DC orienting field for the purpose of generating the property of uniaxial anisotropy in the production films and test-film 10 may be provided by DC electromagnet 24 and DC power source 26.

The test apparatus of the present invention includes a supply reel upon which is wound a ribbon 12 that functions as the substrate means upon which test-film 10 is to be deposited. Ribbon 12 is, in turn, fed through a twister 32 which through twister drive 20 and appropriate mechanical means imparts a cyclical torsional stress to ribbon 12 by causing ribbon 12 to cyclically oscillate about its longitudinal axis. Ribbon 12 is then fed through a guide means 34 and upon a take-up reel 36 which is selectively operated by take-up reel drive 38 and power source 40. Drive field source 42 and associated power source 44 through drive field coil 46 provide, in the area and plane of test-film 10, a varying DC drive field that is oriented perpendicular to the easy axis of test-film 10 for causing test-film 10 to generate a switching field that may be detected by pickup coil 48 which, in turn, is coupled to pickup signal controller 50. Pickup signal controller 50, which is powered by power source 52, detects and amplifies the output signal induced in coil 48 by the switching field in test-film 10. Timing cam 54, which is associated with twister 32, controls timing switch 56 which performs a gating function for the output signal induced in pickup coil 48 during the desired portion of the cyclical stress cycle applied to test-film 10. Pickup signal controller 50 couples the appropriate signals to signal analyzer 58 which may control power source 60 and, correspondingly, the flow of the metalized vapor 62 from source 64. Timing cam 54, through controller 50, also times the pulsed DC field generated by pulsed drive field coil 66 and source 68 that is oriented parallel to and of an opposite polarity than the DC orienting field provided by electromagnet 24.

General method A single preferred method of monitoring the magnetostriction of thin-ferromagnetic-films by peri dically stressing the film during its generation by vacuum deposition is illustrated. The present invention utilizes a novel test apparatus that is placed in the environment in which the deposited layer elements are to be generated. The vaporized material is deposited on a small portion of a continuous glass ribbon, which functions as a test substrate, in the same manner as it is deposited on the production substrates. The continuous glass ribbon is fed from a supply reel, to a twister mechanism, over a suitable mask for defining the area on the glass ribbon upon which the vaporized material is to be deposited, then through a guide means and finally upon a take-up reel. Above the glass ribbon in the area in which the vaporized material is to be deposited is oriented a pickup coil for detecting changes in the switching field of the so-deposited vaporized material. The twister mechanism, through a cam and linkage arrangement, is caused to rotate in alternate directions of rotation inducing a torsional stress in the glass ribbon and, correspondingly, the test-film formed by the vaporized material deposited thereon. Suitable timing controls are provided to properly time, or gate, the pickup coil signals and the associated electronics with the twisting action of the twister mechanism and the correspondingly produced varying switching field in the test-film under the pickup coil.

After the completion of the monitoring of the separate test-film for each deposition step in the continuous series of discrete deposition steps and in between such adjacent deposition steps the take-up reel is energized causing a new portion of the glass ribbon to be placed above the test-film defining mask whereby a new test-film, during the next subsequent deposition step, may be deposited. The twisting-depositing-monitoring operation is repeated for each deposition step providing a continuous series of discrete test-film depositions without requiring deposition system breakdown between discrete deposition steps.

Structure description With particular reference to FIG. 2 there is provided a schematic illustration of the evacuatable environment in which the deposited layer elements of the present invention may be generated. Evacuatable enclosure 14 is preferably similar to that disclosed in the J. C. Bukkila et al. patent application Ser. No. 547,619, filed May 4, 1966, assigned to the Sperry Rand Corporation as is the present invention. The continuous vacuum deposition system such as disclosed in the J. C. Bukkila et al. patent application includes a transport means 70 upon which a plurality of production substrates 72 are transported through the system. A DC orienting field magnet 24 provides a DC orienting field in the area of the production substrate 72 and of ribbon 12 inducing the characteristic of uniaxial anisotropy in the deposited layer elements formed thereon. The so-induced axis of anisotropy, or easy axis, is directed across the evacuatable enclosure 14 orthogonal to the longitudinal axis of ribbon 12. Test apparatus 80, which is the apparatus whereby the cyclical stresses are applied to the ribbon 12 which detects the so-induced switching field in the test-film 10, may be mounted upon any suitable support means 82, preferably in the general area and level of the production substrates 72. Any suitable driving means 84 and 86 for operating the take-up reel 36 and the twister 32, respectively, may be utilized. It is preferred that the takeup reel drive 38 and the twister drive 20see FIG. 1- be located external to the evacuatable enclosure 14. Accordingly, drive means 84 and 86 may simply be rotatable drive shafts mounted by suitable bushing means on support means 82 and that pass through the base plate of evacuatable enclosure 14 by any suitable type bearings.

In the preferred embodiment of the present invention the generated elements are formed of a nickeliron alloy material having two stable remanent magnetic states and reasonable drive field requirements. The aforementioned Rubens et al. Patent No. 2,900,282 discloses one method of generating such memory elements utilizing a crucible melt source wherein there are produced mem ory elements having the property of uniaxial anisotropy, exhibiting substantially no magnetostriction and exhibiting single domain properties. Such films may be of approximately 81.5% Ni-18.5% Fe and of approximately 100 to 3,000 angstroms (A.) in thickness and are referred to as thin-ferromagnetic-films. Thin films when subjected to an external magnetic field parallel to the plane of the film exhibit the magnetic characteristic of having single domain properties. In a film having such properties the magnetization may be represented by a vector quantity M having both amplitude and direction, the remanent direction being in alignment with the easy axis generated by the orienting DC fieldsuch as generated by electromagnet 24.

Internal to evacuatable enclosure 14 and mounted on a bottom plate thereof there is shown a supporting means 88 for orienting the material source 64. Source 64 is, in the preferred embodiment of the present invention, a crucible melt source such as that utilized in the aforementioned Rubens et a1. Patent No. 2,900,282 which is controlled by the heater power source 60 of FIG. 1. The heated melt vaporizes and some of the vapor particles 62 emanating therefrom move in an upward direction into the area of the substrate members 72 and 12. As will be discussed in greater detail below, the vapor particles 62 pass through a hole 90 in the body of test apparatus 80, through a test-film defining mask and are then deposited upon the bottom surface of ribbon 12. Additionally, some of the vapor particles 62 move in an upward direction toward production substrate 72 whereby a suitable masking means 76 defines the soformed production run elements 74 on the under side of substrate 72.

With particular reference to FIG. 3 there is presented a near side view of test apparatus 80 of the present invention. Test apparatus 80 includes a metal body 100 upon which are mounted take-up reel 36 and its support 37, supply reel 30 and its support 31, and twister 32 and its aft support 106. Drive field assembly 102,

which by coil 46 provides the drive field for inducing the switching field in the test-film 10 and by coil 66 provides the pulsed DC field to cancel the DC orienting field provided by electromagnet 24 is mounted above ribbon 12 upon a forward support 104 and support 106 which also functions as a supporting means for twister 32. Along the near side of body 100 there is provided an aperture by which the upwardly directed vapor particles 62 emanating from vapor source 64 pass through body and are deposited upon the under side of ribbon 12. Additionally, there are provided leads 110, 112 for the heating elements internal to body 100 and the thermocouple 114, and associated input element 116, that monitors the temperature internal to body 100 as provided by the internal heating elements associated with leads 112.

With particular reference to FIG. 4 there is presented a top view of test apparatus 80 of the present invention for aiding in the orientation of the components illus trated in FIG. 3. This view particularly illustrates the orientation of assembly 102 upon its fore and aft sup ports 104 and 106, respectively. Assembly 102 includes two drive field coils 66a, 66b, forming coil 66 of FIG. 1, that are mechanically intercoupled by central support 124. Mounted thereon are a plurality of electrical leads 126 that provide electrical interconnection to drive field source 42, electrical leads 127 that provide electrical interconnection to pickup signal controller 50 and electrical leads 128 that provide electrical interconnection to DC pulse field source 68 controller 50-see FIG. 1. Additionally, this view illustrates the method whereby ribbon 12, from supply reel 30 passes through twister 32, between drive field coils 66a, 66b of assembly 102 and on to take-up reel 36 as driven by take-up reel 36 drive gear 130. The twister 32 drive arrangement is shown as including a cam 132, cam follower 134, drive gear 136, drive shaft 138 arrangement. Twister drive source 20see FIG. lthrough twister drive gear 136 rotates twister 32 in an oscillating manner about its longitudinal axis, which is also co-linear with the longitudinal axis 160 of ribbon 122. Additionally, there is illustrated a timing gear 54 that is also mounted on shaft 138 and that is driven by twister drive gear 136. Further, timing switch 56 is shown mounted on the far side of body 100 and below timing cam 54. The timing gear 54, timing switch 56 arrangement is utilized to time the pickup coil 48 signals and the associated electronics of pickup signal controller 50 with the cyclical twisting action of twister 32 and the correspondingly produced varying torsional stress in test-film 10 under pickup coil 48.

With particular reference to FIG. 5 there is presented a cross-sectional view of test apparatus 8 0 of the present invention taken along axis 5-5 of FIG. 3. This view is presented to particularly point out the vertical relationship of pickup coil 48 and drive field coil 46, which are mounted in a stacked relationship upon the center support 124 of assembly 102, ribbon 12 and test-film 10, which is formed upon the bottom surface thereof by the the metalized vapor 62 passing through apertures 90 and in body 100 and through mask 152. Additionally, there are illustrated the heating elements 154, 156 that are controlled by any appropriate heater power source coupled to terminals 110, 112see FIG. 4. Heating elements 154, 156 are utilized in a well known manner to maintain the desirable metal vapor 62 and ribbon 12 temperatures for optimum thin-ferromagnetic-film generation.

With particular reference to FIG 6 there is presented a partial top view of test apparatus 80 of the present invention taken along axis 66 of FIG. 3. This view particularly illustrates the orientation of ribbon 12 along its longitudinal axis 160 after emerging from supply reel 30, passing through twister 32, emerging therefrom under pressure pad 162 and spring 164, passing over mask 152 and entering guide means 34, entering under pressure pad 166 and spring 168 and exiting therefrom under guide strip 170 to pass on and upon take-up reel 36. Additionally, there are illustrated the supports 172 and 106 of twister 32 which provide the restraining and guide means which restrain twister 32 in all but a rotational manner about its longitudinal axis 160. Along the right hand end, or aft end, of twister 32 there is illustrated the arrangement whereby twister 32, through cam follower 134, is held in compressive restraint against the edge of cam 132. This compressive restraint of twister 32 with respect to cam 132 is provided by spring 178, which at one end is attached to support 106 by screw 174 and at the other end is attached to twister 32 by a pin 176. Spring 178, by compressively restraining cam follower 134 against cam 132-see FIG. 4-causes twister 32 to obtain the alternate clockwise, counterclockwise rotational direction for imparting the desired cyclical stresses to ribbon 12 and, accordingly, test-film deposited thereon.

With particular reference to FIG. 7 there is presented an end view of guide 34 of test apparatus 80 of the present invention taken along axis 77 of FIG. 6. This view particularly illustrates the orientation of ribbon .12 in the channel formed along the top surface of guide 34 as it is compressively held therein by ceramic pad 166 and spring 168.

With particular reference to FIG. 8 there is presented an end view of support 172 of test apparatus 80 of the present invention taken along axis 8-8 of FIG. 6. This view particularly illustrates the orientation of ribbon 12 emerging from twister 32 in a channel-like depression and compressively held therein by ceramic pad 162 and spring 164. Guide 172 secures twister 32 along its longitudinal axis 160 within a recess in support 106 restraining its fore and aft movement along its longitudinal axis 160 while permitting free movement rotationally about its longitudinal axis 160. Support 172 consists of bottom suport 180 and top support 182 rigidly secured about twister 32 and to each other by bolts 184 secured to body 100 by bolts 186.

With particular reference to FIG. 9 there is presented a partial end view of the twister cam 132, cam follower 134 and timing cam 54 arrangement of test apparatus 80 of the present invention taken along axis 9-9 of FIG. 3. This view particularly illustrates the twister cam 132, cam follower 134, drive gear 136, drive shaft 138 arrangement illustrated in the top view of FIG. 4. The assembly of drive gear 136, twister cam 132 and timing gear 54 upon shaft 138 is supported by support means 190 and 192 upon body 100 whereby the proper relationship is maintained between cam 132 and cam follower 134 for imparting the required cyclical rotation to twister 32. Additionally, there is illustrated therein the relationship of spring 172 wound about twister 32 compressively holding, by screw 174 and pin 176, cam follower 134 against twister cam 132. Further, there is illustrated the means whereby timing switch 56 and its switch arm 194 are oriented in a vertical relationship with timing cam 54 by means of mounting plate 196.

With particular reference to FIG. 10 there is presented a partial side view of the timing cam 54, timing switch 56 arrangement of test apparatus 80 of the present invention taken along axis 10-10 of FIG. 9. This view particularly illustrates the orientation of timing switch 56 upon its mounting bracket 196 whereby its switch arm 194 rides the peripheral surface of timing cam 54 gating, over the time duration of cam members 197, 198, the pickup coil 48 and pulsed DC drive field coil 66 signals and the associated electronics of pickup signal controller 50 with the cyclical twisting action of twister 32 and the correspondingly produced varying torsional stresses in test-film 10 under pickup coil 48.

With particular reference to FIG. 11 there is presented a schematic illustration of the orientation of the DC orienting field 204, the varying DC drive field coil 46,

the pickup coil 48, the pulsed DC drive field coil 66 and the cyclical torsional stresses with respect to test-film 10 and the ribbon substrate 12 of the present invention. This schematic illustration illustrates that the axis of anisotropy, or easy axis, 210 of test-film 10 is in the plane of test-film 10 and is aligned orthogonal to the longitudinal axis 160 of ribbon 12. Additionally, the magnetic axes of pulsed DC drive field coil 66, varying DC drive field coil 46 and of pickup coil 48 are orthogonal to, parallel to and parallel to, respectively, the easy axis 210 test-film 10. With twister 32 imparting clockwise (CW) or counterclockwise (CCW) cyclical torsional stresses to ribbon 12 and with the metallic vapor particles 62 being deposited upon the under side of ribbon 12 through the mask 152 and forming the test-film 10 thereon, as illustrated, the application of a drive field by means of drive field coil 46 transverse to the magnetization M of test-film 10 while concurrently pulsed DC drive field coil 66 is cancelling the DC orienting field such magnetization of test-film 10 oscillates about its easy axis 210 inducing in pickup coil 48 an output signal the nature of which is analyzed by pickup signal controller 50 for an indication of the varying magnetostrictive characteristics of test-film 10 during its generation process. The analysis of the output signal induced in pickup coil 48 and its relationship with the magnetostriction characteristics of test-film 10 may be similar to that of the P. E. Oberg et al., Patent No. 3,336,154, and, accordingly, no detailed discussion of the analysis of the test-film 10 magnetostriction characteristics shall be given herein. However, it is to be understood that any one of many well known arrangements for the generation and detection of the switching field in the test-film 10 during this generation process may be utilized with the test apparatus of the present invention, it being understood that there is no limitation intended to be construed to that of the preferred embodiment of the present invention.

With particular reference to FIG. 12 there is presented a plot of degrees rotation of timing cam 54 versus torsional stress induced in test-film 10 over a period of one complete rotation, i.e., 360 degrees, of timing cam 54 showing typical CW and CCW sampling periods of 20 degrees during the times of maximum stress in test-film 10. In the preferred embodiment of the present invention timing cam 54 was driven at a frequency of three cycles per second by twister drive 20 while the varying DC drive field coil 46 generated a 10 oersteds maximum magnetic drive field of 455 kHz. transverse to easy axis 210 of test-film 10 (with the DC orienting field of 30 oersteds provided by electromagnet 24 cancelled by the pulsed DC drive field provided by coil 66 during the sampling periods). Simultaneous with the application of the DC orienting field twister 32 induces the cyclical torsional stress, defined by wave form 120, in test-film 10 which stress approaches that of a well known sine wave. By establishing the relationship of the cam surfaces 197, 198 of timing cam 154 to be aligned with switch arm 194 of timing switch 56 at the times of maximum clockwise and counterclockwise torsional stress induced in ribbon 12, as at degrees and 270 degrees rotation of the timing cam 54, timing switch 56 may be adjusted to be actuated over a sufficient period of time, e.g., 20 degrees, to provide the necessary timing for gating the output signal detected by pickup coil 48 into pickup signal controller 50 over only that narrow period of time, e.g., 20 degrees, that is necessary to be sampled and analyzed. With the cam 132, cam follower 134 utilized in the illustrated embodiment, twister 32 was caused to oscillate in a cyclical manner about its longitudinal axis approximately 14 degrees in both the clockwise and counterclockwise directions at a rate of three cycles per second. The timing switch 56, timing gear 54 arrangement was such as to provide a sampling gate of approximately 20 degrees centered about the maximum induced stress points of 90 degrees and 270 degrees, i.e., clockwise and counterclockwise, rotation of ribbon 12. The two 20 degree sampling windows over one complete revolution of timing cam 54 was found to be satisfactory to provide a meaningful output signal that could be utilized by pickup signal controller 50.

Operation Deposition of test-film 10 upon ribbon 12 and of the production run elements 74 upon production substrates 72 is initiated by installing test apparatus 80 within evacuatable enclosure 14 with glass ribbon 12 mounted upon supply reel 30, through twister 32, guide means 34 and upon take-up reel 36. I

The following steps, not necessarily in order given, are then performed preparatory to generating the test-film 10 upon ribbon 12 and the production run memory elements 74 upon production substrates 72:

(1) The evacuatable enclosure 14 is sealed and electrical power from power source 18 is coupled to vacuum pump 16 so as to provide the desired operating pressure within evacuatable enclosure 14.

(2) Electrical power from an appropriate source is coupled to heater element 78 so as to preheat production substrate 72 to the desired temperature prior to forming elements 74 thereon.

(3) Electrical power from an appropriate source is coupled to heater elements 154, 156 within body 100 of test apparatus 80 so as to preheat ribbon 12 to the desired temperature prior to forming test-film 10 thereon.

(4) Electrical power from DC field power source 26 is applied to electromagnet 24 so as to generate the DC orienting field necessary to provide the desired magnetic characteristic of uniaxial anisotropy in elements 74 upon substrate 72 and in test-film 10 upon ribbon 12.

(5) Electrical power from power source 44 is coupled to drive field source 42 and coil 46 so as to generate by varying DC drive field necessary to switch the magnetization'M of the to-be-generated test-film thereby generating a switching field that is to be detected by pickup coil 48.

(6) Electrical power is coupled from power source 22 to twister drive 20 causing twister 32 to induce cyclical torsion stresses in the to-be-generated test-film 10 on ribbon 12.

After completion of the preparatory steps 1-6 above, actual generation and monitoring of the varying magnetostrictive characteristics of test-film 10 and elements 74 may then be initiated. The following steps, not necessarily in the order given, are then performed to generate layered elements having the desired magnetostrictive characteristics:

(1) Electrical power from heater power source 60 is coupled to melt source 64 which power heats the metal held therein causing such metal to vaporize into the upward direction flowing metallic vapor 62. The vapor particles 62 emanating from source 64 move into the areas of substrates 72 and 12 that are exposed by masks 74 and 152, respectively.

(2) Pickup coil 48, during the CW and CCW sampling periods noted in FIG. 12, detects the switching field generated by the switching of the magnetization of test-film 10 on ribbon 12 as caused by the driving field produced by drive field coil 46 and as permitted by the pulsed DC drive field provided by coil 66 cancelling the DC orienting field provided by electromagnet 24. The detected switching field that is magnetically coupled to pickup coil 48 generates an output signal therein that is coupled to pickup signal controller 50. Timing switch 56 through switch arm 194 upon the surface of timing cam 54 gates the pickup signal induced in pickup coil 48 into pickup signal controller 50 in the specified time relationship, e.g., during the CW and CCW sampling periods noted in FIG. 12, corresponding to the maximum applied torsional stress in test-film 10.

(3) The pickup signal that is gated into pickup signal controller 50 is monitored and analyzed by signal analyzer 58 as to its indication of the magnetostrictive characteristics of test-film 10and indirectly that of production elements 74.

(4) When it is determined that test-film 10 has the desired magnetostrictive characteristic, the generation of test-film 10 and elements 74 is halted.

(5) A new production substrate 72 is moved in place over mask 74 in preparation for the next consecutive discrete deposition step.

(6) Power source 40 couples an appropriate signal to take-up reel driver 38 causing take-up reel 38 to reel-in a small portion of glass ribbon 12 causing a new portion of glass ribbon 12 to be placed above the test-film mask 152 whereby a new test-film 10, during the next subsequent deposition step, may be deposited thereon.

(7) The actual generation and monitoring of the varying magnetostrictive characteristics of test-film 10 during this and next subsequent deposition steps is conducted as discussed with respect to steps 2-6 above.

It is apparent that there has been disclosed herein a device for and a method of monitoring the varying magnetostrictive characteristics of a deposited layer element, or test-film, during the generation thereof by applying cyclical stresses thereto and detecting the resulting varying switching field thereof. Having now, therefore, fully illustrated and described my invention what I claim to be new and desire to protect by Letters Patent is set forth in the appended claims.

What is claimed is:

I. A method of generating a deposited-layer element having a desired magnetostriction, comprising the steps of:

placing a continuous substrate member on supply and take-up means in a deposited-layer magnetostrictivealloy element generating environment; orienting a predetermined portion of said substrate member in the area of an element defining mask;

initiating the vaporization of a magnetostrictive alloy for generating said element in said predetermined portion of said substrate member;

imparting a cyclical torsional stress to said substrate member in the area of said element during the generation of said element;

providing a DC orienting field in the area of said element for inducing an easy axis in the plane of said element; providing a varying intensity drive field in the plane of said element that is oriented substantially transverse said easy axis for causing said element to generate a varying switching field;

monitoring said varying switching field;

halting said elements generation process when said element has the desired magnetostrictive characteristic; and,

selectively driving said take-up means for positioning a different predetermined portion of said substrate member in the area of said element defining mask for each deposition step in a continuous series of diecreate deposition steps.

2. An apparatus for monitoring the magnetostrictive characteristics of a deposited-layer element that is generated from a vaporized alloy, comprising:

means for generating a vaporized alloy;

supply and take-up means for holding a continuous substrate member;

means for orienting a predetermined portion of said substrate member in an area of said vaporized alloy for forming a deposited-layer element thereon; means for selectively driving said take-up means for positioning said predetermined portion of said substrate member in said area of said vaporized alloy; said orienting means including a stress inducing means;

and,

means for actuating said stress inducing means for imparting a cyclical stress to said substrate member in the area of said element during its formation.

3. The apparatus of claim 1 wherein said stress inducing means is a twister means for imparting a cyclical torsional stress to said element.

4. The apparatus of claim 3 further including means for providing a DC orienting field in the area of said element for inducing an easy axis in the plane of said element.

5. The apparatus of claim 4 further including means for providing a varying intensity drive field in the plane of said element that is oriented substantially transverse said easy axis for causing said element to generate a varying switching field.

6. The apparatus of claim 5 further including monitoring means for detecting said varying switching field.

7. The apparatus of claim 6 wherein said actuating means provides control of said monitoring means.

8. The apparatus of claim 5 further including means for halting the generation of said element when said element has the desired magnetostrictive characteristic.

9. The apparatus of claim 8 wherein said driving means positions a difierent predetermined portion of said substrate member in the area of said vaporized alloy for each deposition step in a continuous series of discrete deposition steps.

References Cited UNITED STATES PATENTS 3,336,154 8/1967 Oberg et a1. 117-107 x 3,418,163 12/1968 Oberg et a1. 117-107 x ANDREW G. GOLIAN, Primary Examiner US. Cl. X.R. 

